I'm using Windows XP service pack 1, pentium 4 512 Mb Ram 2.66Ghz. AVG resident shield periodically tells me that I have a 'trojan horse downloader.dyfica.w' and then tells me the location is 'C:System Volume Information:Restore:(3 different files)' it then asks me to run AVG to remove. I have run AVG and Sophos and housecall and none of them can find the virus never mind remove it? I've scanned the whole PC, just C: drive and just the system vol info file. I can't just go into the system vol info file to delete what I want as it's read only. Is there a way I can access this file or anything else you can suggest?